Formal specification of discrete systems by active predicates and dynamic constraints

In this short paper we sketch an enhancement of our co-notation, a specification language for the behavioural description of a wide class of information processing systems which supports a constraint-oriented specification style. The enhancement substantially improves previous versions of the notation by allowing for the dynamic creation and elimination of constraints. The formal, operational semantics of the (extended) co-notation has been re-designed in a form which should favour both the exploration of further variants of the notation and its object-oriented implementation.